Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-78209— exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values

Quick assessment

Affected
exceljs exceljs
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

exceljs-hardened 版本在 5.0.0 之前，未能对写入 CSV 输出内容的单元格值中的前导等号（=）、加号（+）、减号（-）或 at 符号（@）进行中和处理。攻击者若能够影响导出的单元格值，便可注入可在电子表格应用程序中打开 CSV 文件时执行的公式，从而可能导致数据外泄或其他恶意行为。

CVSS 8.2 · High EPSS 0.29% · P22

Affected Version Matrix 1

VendorProduct Version RangeStatus
exceljs exceljs ≤ 4.4.0 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-78209

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values
Source: CVE Program / CVE List V5
Vulnerability Description
exceljs-hardened versions before 5.0.0 fail to neutralize leading equals, plus, minus, or at signs in cell values written to CSV output. Attackers who can influence exported cell values can inject formulas that execute when the CSV file is opened in a spreadsheet application, potentially exfiltrating data or performing other malicious actions.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
CWE-1236
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
exceljs exceljs 0 ~ 4.4.0 -

II. Public POCs for CVE-2026-78209

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 49721 chars
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
100+ AI POC generations per month

III. Intelligence Information for CVE-2026-78209

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-78209 (2)

Vendor Pages for CVE-2026-78209 (1)

Same Patch Batch · exceljs · 2026-08-24 · 4 CVEs total

CVE-2026-78207 9.4 CRITICAL exceljs through 4.4.0 Prototype Pollution via deepMerge Reached From Note Serialization
CVE-2026-78206 7.5 HIGH exceljs through 4.4.0 Uncontrolled Resource Consumption via Unbounded xlsx Decompression
CVE-2026-78208 7.5 HIGH exceljs through 4.4.0 Path Traversal via Unvalidated addImage filename

IV. Related Vulnerabilities

Same product: exceljs
Same vendor: exceljs
Same weakness: CWE-1236

V. Comments for CVE-2026-78209

No comments yet

Leave a comment